Water-tight electric cable

DETAILED DESCRIPTION What is claimed is: 1.
An electric cable having a core of a plurality of insulated conductors and a jacket, the area between the conductors and within the jacket being at least partially filled with a particulate water-swellable, water-insoluble polymer which comprises: (a) from about 15% to about 50% by weight of an olefinically-unsaturated carboxylic acid containing an activated carbon-to-carbon olefinic double bond and at least one carboxy group; (b) from about 49.
07% to about 82% by weight of an alkyl acrylate wherein the alkyl group has from 1 to 6 carbon atoms; and (c) from about 0.
03% to about 3.
0% by weight of a crosslinking agent which are polyunsaturated polymerizable vinyl monomers containing two or more free radical polymerizable ethylenic groups, said crosslinking agent being introduced directly into the carbon-carbon backbone of the polymer.
2.
The electrical cable of claim 1 in which the polymer comprises from about 20% to about 40% by weight of the olefinically-unsaturated carboxylic acid selected from the group consisting of methacrylic acid and acrylic acid; from about 59.
02% to about 78% by weight of an alkyl acrylate selected from the group consisting of methyl acrylate, ethyl acrylate and n-butyl acrylate; and about 0.
08% to about 2% by weight crosslinking agent.
3.
The electrical cable of claim 1 wherein the polymer is contained in an absorbent wrapping comprising an absorbent layer containing up to 90% by weight of said particulate water-swellable, water-insoluble polymer.




Description:
This invention relates to insulated electrical devices protected against the entry and migration of water, and particularly to insulated electrical devices containing a novel solid, water-swellable, water-insoluble polymer.
Water penetration of insulated electrical devices and especially plastic insulated multiconductor telephone cables can seriously effect the electrical properties of such structures.
The problem of water penetration is amplified when the electrical device is positioned underground or in a high humidity environment